Non-TC Rated Cable in a Cable Tray

[Chris3585]

I am working to try to get a contractor out of a bind. They have installed non-TC rated cable within a cable tray and it would be very costly to remove and replace the cable with new TC rated cabling. We are weighing two options, either:

-Enclosing the entire cable tray with an enclosed wireway
-Or installing the non-TC rated cabling within an enclosed wireway on top of the cable tray.

These both appear to be NEC compliant solutions. Does anyone agree or disagree? Has anyone else run into this situation before?

 

[Smart $]

What type of cable was installed?

 

[Chris3585]

Stabiloy FeederPlex HS XHHW-2 Aluminum

 

[Smart $]

... We are weighing two options, either:

-Enclosing the entire cable tray with an enclosed wireway
-Or installing the non-TC rated cabling within an enclosed wireway on top of the cable tray.

...

Stabiloy FeederPlex HS XHHW-2 Aluminum

I don't see any problem with either of your proposed solutions... but I have to wonder about the cost savings over replacing :blink:

 

[Chris3585]

It is a large manufacturing facility with large, long feeders. It would be a great cost to replace all the wiring that has been installed to date. Thanks for the second opinion.

 

[eric9822]

I have to wonder about the cost savings over replacing :blink:

I agree. Purchasing and installing a bunch of wireway in tray sounds pretty labor intensive. Encasing tray in wireway sounds even more labor intensive. I assume both wireway and conductor replacement have been estimated?

 

[Chris3585]

With the type of cable tray this is, they only need to fabricate covers for the top and bottom. There are (2) 3200 amp, 480 volt electrical service feeding the circuits in the cable trays. It is a lot of cable and I am pretty sure the contractor has priced out both options.

 

[don_resqcapt19]

With the type of cable tray this is, they only need to fabricate covers for the top and bottom. There are (2) 3200 amp, 480 volt electrical service feeding the circuits in the cable trays. It is a lot of cable and I am pretty sure the contractor has priced out both options.

That would just be fully enclosed cable tray and the wire still would be non-compliant.

 

[eric9822]

With the type of cable tray this is, they only need to fabricate covers for the top and bottom. There are (2) 3200 amp, 480 volt electrical service feeding the circuits in the cable trays. It is a lot of cable and I am pretty sure the contractor has priced out both options.

Thats's not a wireway, that's a cable tray with covers. IMHO.

 

[Smart $]

That would just be fully enclosed cable tray and the wire still would be non-compliant.

Thats's not a wireway, that's a cable tray with covers. IMHO.

I agree.

Metal wireway is not required to be listed, but it is required to be marked with the manufacturers name or trademark and visible after installation: 376.120.

If fabricating, it would have to wrap entirely around the cable tray... or simply remove the tray as the wireway is installed, the same way you would do when replacing [damaged, corroded] cable tray. Don't forget fill requirements are different when sizing the wireway.

 

[rbalex]

I agree.
...

I also agree and it?s too bad. Although 90.1(C) implies otherwise, the NEC is becoming more and more a ?design specification? for persons untrained or trained; especially with greater and greater demands for listing everything. It may make some things easier for AHJs but it makes specific professionally engineered solutions more and more difficult.

Assuming the conductors are otherwise properly installed per Article 392 the biggest problem is they take a heavy ampacity hit per Section 392.11. Otherwise, except for "non-compliance" there?s no real reason your first solution (enclosing the tray) should be unacceptable ? even for most Table 310.13(A) single conductors not specifically listed for cable tray use (they should still be #1/0 or larger). Trays aren?t listed either; they are a support system [Section 392.2]. Actually, if the entire installation is indoors and/or the conductors are sunlight resistant, unless something else has been undislosed, there is no significant technical or safety reason to do much of anything.

This is an ideal case for having a qualified ­engineer evaluate and seal the design and seek a Section 90.4, second paragraph, ?special permission.?

 

[Chris3585]

Thanks, Bob.

I came to a similar conclusion. The conductors would have been protected within the modified cable tray, which from what I understand is the main advantage of TC cable. The contractor saw me as the qualified engineer and wanted my approval.

Unfortunately for the contractor, someone with the owner rejected the idea (after a lower person with the owner originally approved it) and now the contractor will have to pull TC cable.

 

[don_resqcapt19]

Assuming the condutors are 1/0 or larger, why didn't the manufacturer get the CT listing for the conductors? There is a lot of single conductor XHHW from other manufacturers that has the "CT" marking and listing.

 

[Chris3585]

Don,

It turns out that the non-TC rated cable was a "Value Engineered" item, so it was less than the originally quoted TC cable for the project. No one picked up on the fact that the VE cable was non-TC rated. I would assume the TC cabling costs more than non-TC (either by jacket construction or listing fees or both). Most of the conductors are 500 KCMIL.

Chris

 

[don_resqcapt19]

Don,

It turns out that the non-TC rated cable was a "Value Engineered" item, so it was less than the originally quoted TC cable for the project. No one picked up on the fact that the VE cable was non-TC rated. I would assume the TC cabling costs more than non-TC (either by jacket construction or listing fees or both). Most of the conductors are 500 KCMIL.

Chris

It appears to me that the "cable" is nothing more than a factory twisted bundle of single conductors. Most of the single conductors that I see in sizes 1/0 and larger are listed for use in cable trays. I am somewhat surprised that these single condutors are not so listed. It puts that manufacturer's product at a comptetive disavantage with other manufacturers who have their single conductor XHHW listed for use in cable tray. As far as I know those manufacturers do not increase the price for the "CT" listed single conductors. Note, I do not see a need for this factory bundle of single conductors to be listed as "tray cable". I only see a need for the individual conductors to be listed and marked for CT use.

The manufacturer in question also makes tray cable, and maybe the lack of a CT rating on these single conductors is just an attempt to get the customer to by the more expensive tray cable product.

 

[rbalex]

Assuming the condutors are 1/0 or larger, why didn't the manufacturer get the CT listing for the conductors? There is a lot of single conductor XHHW from other manufacturers that has the "CT" marking and listing.

Who knows why a manufacturer decides to list something for a specific purpose? In this case, sunlight resistance is about the only requirement beyond "regular" properties necessary. But I know it wouldn't have been too long ago, when no one would have blinked an eye over a cable tray installation using general building wires that were 1/0 or larger - at least in industrial designs. As I said, the trend to list/label for virtually every specific application has severely restrained solid designs but have shown no appreciable safety advantage. It's the reason 500.8(A) exists. There were enough "Users" on CMP14 that recognized listing/labeling wasn't necessary for selecting everything under qualified designers.

I already agreed the proposed design is "non-compliant"; it just isn't unsafe IMO unless there is some other undisclosed flaw.

 

[Chris3585]

There must be a cost component. To the best of my knowledge Lapp does not make an aluminum multi-conductor tray cable (only copper). I do not know the reason, but now I am curious enough to find out. We do specify multi-conductor tray cabling in manufacturing (which are smaller than #1/0). The German companies specificaly prefer to use Tray Cable in lieu of wire in conduit.

 

[weressl]

I also agree and it?s too bad. Although 90.1(C) implies otherwise, the NEC is becoming more and more a ?design specification? for persons untrained or trained; especially with greater and greater demands for listing everything. It may make some things easier for AHJs but it makes specific professionally engineered solutions more and more difficult.

Assuming the conductors are otherwise properly installed per Article 392 the biggest problem is they take a heavy ampacity hit per Section 392.11. Otherwise, except for "non-compliance" there?s no real reason your first solution (enclosing the tray) should be unacceptable ? even for most Table 310.13(A) single conductors not specifically listed for cable tray use (they should still be #1/0 or larger). Trays aren?t listed either; they are a support system [Section 392.2]. Actually, if the entire installation is indoors and/or the conductors are sunlight resistant, unless something else has been undislosed, there is no significant technical or safety reason to do much of anything.

This is an ideal case for having a qualified *engineer evaluate and seal the design and seek a Section 90.4, second paragraph, ?special permission.?

Wouldn't the vertical flame test be still aplicable, even if it is an indoor installation?

 

[John120/240]

I already agreed the proposed design is "non-compliant"; it just isn't unsafe IMO unless there is some other undisclosed flaw.

I like this quote. Thank You rbalex

 

[rbalex]

Wouldn't the vertical flame test be still aplicable, even if it is an indoor installation?

Sorry for not getting back sooner. Single conductor building wires had ICEA/IPCEA, UL, IEEE and/or NEMA "flame test" requirements for ages. The vertical tests were introduced when "cable support" systems became "cable tray" installations and started becoming recognized beyond "industrial" applications, especially multistory commercial. As usual, more constraints than necessary were added to make it "safer" not just safe. The tests were designed primarily for multiconductor PVC jacketed systems.

I have no problem drawing the line between "safe" and "unsafe" and pretty much ignoring the dollars. But when a Proposal to make something "safer" is made, it should also be justified economically.